Codec import adds huge bloat

[drasko]

Looks like codec import makes binaries to be huge:

drasko@Marx:~/go/src/github.com/mainflux/mainflux/cmd/normalizer$ goweight 
   10 MB github.com/mainflux/mainflux/vendor/github.com/ugorji/go/codec
  3.4 MB net/http
  3.0 MB runtime
  2.0 MB github.com/mainflux/mainflux/vendor/github.com/gogo/protobuf/proto
  1.7 MB github.com/mainflux/mainflux/vendor/golang.org/x/net/http2
  1.7 MB net
  1.6 MB github.com/mainflux/mainflux/vendor/github.com/golang/protobuf/proto
  1.4 MB reflect
  1.2 MB github.com/mainflux/mainflux/vendor/google.golang.org/grpc
  1.2 MB github.com/mainflux/mainflux/vendor/github.com/prometheus/client_golang/prometheus/promhttp
  1.0 MB github.com/mainflux/mainflux/vendor/golang.org/x/sys/unix
  1.0 MB github.com/mainflux/mainflux/vendor/github.com/prometheus/client_golang/prometheus
  945 kB github.com/mainflux/mainflux/vendor/google.golang.org/grpc/internal/transport
  933 kB crypto/tls
  872 kB math/big
  753 kB encoding/gob
  714 kB syscall
  633 kB crypto/x509
  627 kB text/template
  596 kB encoding/xml
  574 kB github.com/mainflux/mainflux/vendor/github.com/nats-io/go-nats
  547 kB encoding/json
  510 kB html/template
...

Typically, binary that was expected to be ~3-4MB in size wight now 14MB just because it imports codec.

[ugorji]

Yes,

Basically, generated code increases the size of the package. Generated code occurs when we generate the fastpath helpers, and when users explicitly use codegeneration.

To override using the fastpath, build with the tag notfastpath.

However, be aware that a significant performance benefits occurs from its use. For example, look at the examples below running benchmarks with and without notfast path:

cd bench
go test -run Nothing -bench Benchmark__Cbor_______Decode -benchmem -benchtime 5s -tags ""
go test -run Nothing -bench Benchmark__Cbor_______Decode -benchmem -benchtime 5s -tags "notfastpath"

results:

Benchmark__Cbor_______Decode-8   	   55899	    103707 ns/op	   35520 B/op	     368 allocs/op
Benchmark__Cbor_______Decode-8   	   41484	    137589 ns/op	   39128 B/op	     500 allocs/op

As you can see, at least in this representative benchmark, we get about 33% increase in time per decode operation. Of course, YMMV. And the reduction in size may be worth it, and also most of the types supported in the fastpath may be unnecessary for your use-case.